I’m kind of shocked that I am having to write about warning folks to not skip their RhoGAM shot.

“Prophylactic anti-D immune globulin should be offered to unsensitized Rh D-negative women at 28 weeks of gestation. Following birth, if the infant is confirmed to be Rh D positive, all Rh D-negative women who are not known to be sensitized should receive anti-D immune globulin within 72 hours of delivery.”

ACOG on Prevention of Rh D Alloimmunization

Unfortunately, like with the vitamin K shot, in addition to trying to scare new moms away from getting vaccines, they also tell them to skip their RhoGAM shot.

What is RhoGAM?

RhoGAM (RhIg) or anti-D immune globulin is not a vaccine.

A RhoGAM shot can help prevent hemolytic disease of the fetus and newborn.

It is a prescription immune globulin shot that is given to some pregnant and post-partum women to prevent Rh (Rhesus) immunization, which can lead to hemolytic disease of the fetus and newborn if you get pregnant again.

RhoGAM was approved by the FDA in 1968.

RhoGAM Questions and Answers

If you have been educated about RhoGAM on the Internet and are thinking about skipping your RhoGAM shot, it might be time for a little more research:

What is hemolytic disease of the fetus and newborn (HDFN)? It is not to be confused with vitamin K deficiency bleeding, which can be prevented with a vitamin K shot. Also known as erythroblastosis fetalis, HDFN occurs when a mother develops antibodies against her baby’s own red blood cells and destroys them, leading to anemia, jaundice, and edema. In severe cases, this can be life-threatening and the baby can develop hydrops fetalis.

Why would a mom develop these antibodies against her own baby’s blood in the first place? Since a baby’s blood type is determined by both their mom and dad’s blood type, it is easy to see how it might be different than moms. This usually isn’t a problem, after all, a mother’s immune system doesn’t usually attack any other cells of the placenta or her baby (immune tolerance of pregnancy) that might be “foreign.” Unfortunately, it is not uncommon for a baby’s blood and “foreign” red blood cells to mix with mom’s blood, which could trigger antibodies to form.

How does a baby’s blood mix with mom’s blood? Doctor’s have long known that while mixing is not common during a women’s pregnancy, it can commonly occur when she gives birth, explaining how Rh disease used to kill 10,000 babies each year in the United States. It doesn’t take trauma, a procedure (amniocentesis or chorionic villus sampling), or a difficult delivery for a baby’s blood cells to leak into a mother’s bloodstream. It can just happen. Mixing can also happen after a miscarriage, an ectopic pregnancy, or an induced abortion. Simply trying to turn a baby from the breech to a head-down position before delivery (external cephalic version procedure) leads to fetal-maternal hemorrhage in 2 to 6% of cases.

Who needs to get a RhoGAM shot? It is hopefully clear already that not everyone is at risk to develop Rh immunization and so not everyone needs RhoGAM. Some folks can safely skip their RhoGAM shot, but only because it would never have been recommended for them in the first place. You only need RhoGAM if your baby’s blood type might be different than yours, specifically the Rh D antigen of the blood and if you (mom) are Rh D negative (Rh-negative). Why don’t we worry about the ABO part? While an ABO incompatibility can also cause hemolytic disease of the newborn, it is usually much more minor. Why don’t we worry if you are Rh-positive and the baby is Rh-negative? If your baby is Rh-negative, then he or she wouldn’t have any Rh antigens on their red blood cells to make antibodies against.

What is the chance your baby will be Rh-positive? It depends. And is actually more complicated than people think. If dad is Rh-positive, he can be either +/- or +/+, because there are two alleles for the Rh gene and Rh-positive is dominant. So if mom is Rh-negative (she can only be -/-), then their baby could either be +/- or -/-, so has at least a 50% chance of being Rh-positive. On the other hand, if dad is definitely +/+, then there will be a 100% chance that the baby will be Rh-positive. If you are confused now, then you don’t want to think about how two Rh-positive parents can have a Rh-negative baby!

When will I get my RhoGAM shot? The current guidelines are to get a RhoGAM shot at around the 28th week of pregnancy to prevent Rh sensitization for the rest of the pregnancy; within 72 hours after the delivery of an Rh-positive infant; after a miscarriage, abortion, or ectopic pregnancy; or after amniocentesis or chorionic villus sampling.

Can I skip my RhoGAM shot? You can skip your RhoGAM shot if you are already Rh sensitized (because it’s too late and RhoGAM won’t help for any future pregnancies) or if you are Rh-positive. You will know if you are already Rh sensitized because a blood test is done to check for Rh antibodies. When paternity is certain (you know who the father is), and the father is Rh-negative, you can also skip the shot you would get at 28 weeks. You can also skip your RhoGAM shot if your baby is Rh-negative.

How do you know if you are already Rh sensitized? Moms who are Rh-negative get an antibody screen to see if they have Rh antibodies when they are 28 to 29 weeks pregnant.

Why do some women seem to safely skip their RhoGAM shot and have a healthy baby? Like with skipping a vitamin K shot or with skipping or delaying vaccines, the risk of a baby developing hemolytic disease of the fetus and newborn isn’t 100%, so these parents who skipped their RhoGAM shot gambled and got lucky their baby wasn’t harmed.

But don’t they do it differently in other countries? Yes. In the UK, they routinely give all Rh-negative mothers either one dose of RhoGAM at 28-30 weeks or two doses, one at 28 weeks and another at 34 weeks. New mums will also get a shot after their baby is born if their baby is Rh-positive.

Don’t skip your RhoGAM shot if it has been recommended. If you do, you will have a 13-16% chance of becoming Rh sensitized, which can affect your next pregnancy.

RhoGAM Myths

But your OB/Gyn doctor gives you RhoGAM, so why is a pediatrician writing about it?

Because getting RhoGAM prevents hemolytic disease of the fetus and newborn. If you ever see, or hopefully just read about a baby with hydrops fetalis, you will understand why pediatricians don’t want you to skip anything just because of something you read on the Internet, especially myths like:

RhoGAM is a vaccine – not true. RhoGAM is made of antibodies. And while it is a blood product, it is extensively screened and tested for infections. Of course, you shouldn’t skip any of your pregnancy vaccines either, like your flu or Tdap vaccines.

You only need RhoGAM if you have been in a car accident – not true, at all. Again, even in a normal pregnancy, with a “gentle birth,” there can be mixing of blood. And it doesn’t take a lot of blood mixing. As little as 0.1ml of blood (keep in mind that a teaspoon is 5ml) can trigger Rh sensitization.

hemolytic disease of the fetus and newborn is easily treatable – not true. While it might be true for more minor ABO blood incompatibilities, it is not true for Rh disease. If a baby develops hydrops fetalis, they might need intrauterine fetal blood transfusions and an early delivery. After they are born, babies with hydrops fetalis will likely need blood transfusions (because of severe anemia), exchange transfusions (because of extreme levels of jaundice), medicines to manage heart failure, phototherapy, and will likely be on a ventilator to help them breath. And even in a modern NICU, babies with hydrops fetalis still die.

everyone is offered a RhoGAM shot as part of a Big Pharma profit ploy – not true. RhoGAM is only given to moms who are Rh-negative, and since 85% of people are Rh-positive, most are never offered RhoGAM.

you can just wait to see if you want to get the shot later – not true. If you are Rh-negative and skip the pregnancy dose, waiting until your baby is born to see if they are Rh-positive, you may have already become sensitized. Mixing of blood occurs during pregnancy in at least 12% of cases and that is not just with car accidents, procedures, or trauma. Before RhoGAM started to be used during pregnancy, instead of just after, almost 2% of moms still became sensitized. Although that might seem like a small number, when you consider that almost 4 million babies are born in the United States each year, it ends up being a lot of babies at risk for HDFN if moms start skipping their RhoGAM shots.

you can just skip the shot if you don’t want any more kids – not true. Want if you change your mind and decide you do want more kids or have a “happy accident.”

there are natural ways to prevent Rh-sensitization – not true.

Rhogam causes serious side effects – not true. Rhogam is safe and doesn’t cause autism or any of the other serious side effects that you might see listed on sites trying to scare you away from getting your shot.

“First time mothers do not need it. A dose at 28 weeks is unnecessary unless a test shows sensitization has already occurred.” – ridiculously untrue, but I included it to show what kind of advice you will find on some websites. First time mothers definitely could need it, if they are Rh-negative, so that they don’t become sensitized, and if they are already sensitized, a dose isn’t going to help them!

Again, don’t skip your RhoGAM shot.

What To Know About Getting a RhoGAM Shot

There is no reason to skip your RhoGAM shot if it has been recommended for you during or after your pregnancy.